Code printer



il ECR/C SCAN/VER TAPE' Pl/lll-'R WHEEL Feb. 21, 1950 Filed oct. 18,1946 Feb. 2l, 1950 J. l.. FxNcH 2,497,936

CODE PRINTER Filed oct. 1e, 194e s sheets-sheet 2 rrp/c4: 0

cons 42 55am-wr 38; 37 27 I9 i S :I 26 A 2 i/Gm l l MOTOR l//CF .Figo 5CORRECT/01V 64M v 2E /GNAL SFLECT/N 26 RESTORNG CAM INVENTOR JAMES FINCHATTORNEY Patented Feb. 21, `1950 CODE PRINTER James Leslie Finch, EastRockaway, N. Y., assgnor to Radio Corporation of America, a corporationof Delaware Application October 18, 1946, Serial No. 704,155

Claims.

This invention relates to telegraphic printing systems and moreparticularly to a system for automatically operating a telegraph printeror the like from a source of printed code signals.

It is customary in telegraph printing systems to store the incomingsignals until such time as it is desired to translate them or utilizethem for retransmission. Storage means of various types are well knownin the art and may take the form of ink recorders, perforated tapes,telegraphones or the like. The signals thus stored are then utilized toactuate a local transcribing mechanism or for retransmission purposes.Various means for accomplishing the translation of the signals have beendesigned.

It is an object of this invention to provide an improved system whichwill be entirely automatic in its operation and which will require aminimum number of moving parts.

More specically, it is an object of this invention to provide automaticmeans for scanning printed signals and utilizing the loutputs from thescanned signals to actuate corresponding output circuits.

Briefly, in accordance with the invention, the printed signals arescanned by a device which produces correspondingly varying electricalvoltages. These voltages are combined with a plurality of locallygenerated signal voltages corresponding to the characters to betranslated. The locally generated voltages and the signal outputvoltages are combined in equal strength 180 out of phase whereby acurrent flow will be produced during some period of their combination ineach character circuit save the circuit corresponding to the signalbeing received. These currents are utilized to block a source of powerto the output circuits.

For purposes of illustration, a single embodiment of the invention hasbeen selected in which it is assumed that International Morse signalshave been printed on a tape by an ink recorder. These signals arephotoelectrically scanned and the output circuits mentioned are used toactuate the character operating magnets of a tape typewriter. It is tobe understood that the above assumptions are made not by way oflimitation, since many of the features of this invention could be usedfor operating from recorder tape other than the ink recorder variety andfrom codes other than International Morse code. Similarly, the inventioncould be used to actuate a perforator or printer perforator instead of atape typewriter or the equivalent apparatus.

The above and other objects and advantages of the invention will beclear upon a consideration of the following detailed description takenin conjunction with the accompanying drawings, in which:

Figure 1 represents schematically the chosen embodiment of theinvention;

Figure 2 is a detailed drawing illustrating the operation of the camsand contacts and the circuits controlled thereby illustrated in Figure1;

Figure 3 represents a series of curves illustrative of the outputcurrents in the circuits of Figure 1;

Figure 4a represents the output currents from the correction cam whenthe locally generated currents and the signal currents are in phase;

Figure 4b represents the output currents of the correction device whenthe spacing bauds are too short;

Figure 4c represents the output currents of the correction device whenthe spacing bauds are too long; and

Figure 5 represents a modiiication of an element of the invention.

Throughout the drawings, like parts are designated by like numerals. Forthe purpose of simplifying the drawing, it will be noted that in Figure2 certain of the cam operated contacts have been shown in relation totheir position in the circuits which they control as well as in relationto the cam by which they are operated. In such case it is to beunderstood that only one pair of contacts is actually in the system.

Referring to Figure l it will be seen that there has been provided atape l0 carrying International Morse signals which have been printedthereon by any suitable device, such as an ink recorder. The main motorIl drives, through suitable gears l2, a shaft I3 upon which are mounteda plurality of cams i4, l5, I6, l1 and I8, a plurality of code segmentsi9 and an electrically actuated clutch 2U. The clutch drives the tapepuller wheel 2l for advancing the tape I0. The tape puller wheel 2lpulls the tape I0 past a photocell scanner 22. The output of thephotocell scanner will be referred to as the signal.

The signal operates a bar 23 upon which are mounted contact fingers 24.One such contact linger is provided for each pair of code segments I9.These are drawn in the figure with solid lines in their spacing positionand with dotted lines in their marking position.

Each of the contact fingers controls through suitable contacts a gasiilled triode 26 which in turn controls a second gas lled triode 21.These tubes together with their control circuits are arranged within therectangle 28. The above referred to contacts, tubes, etc., control thecharacter operating magnets 26 and the tape advancing magnet 3i?. Thetape typewriter Si prints on tape 32 which is fed from a standard tapereel. Within the rectangle 28 there is also shown the clutch controlapparatus and a ratchet relay control circuit 3d. There is also shown acorrection motor 35, the purpose of which will appear later.

Referring to Figure 2 the cams III, i5, I6, I'I, it, and a typical pairof code segments Iii together with their associated control circuits areshown. It will be understood that similar contacts 24 and theirassociated control circuits are provided for each of the code segmentsI9. Code segment IS has been chosen to represent the gure 0. Thissegment actually consists or" two disks shown one behind the other, theelements on the marking disk being shown as hollow squares while theelements of the spacing disk are shown as solid squares. Associated.with the code segment is shown, in section, the bar 23 carrying acontact finger 2d which in turn actuates a contact 25. The contact 25opens and closes a circuit between a source of negative grid bias 36 andthe control grid 3l of gas triode 2t. A suitable grid leak 33 is placedbetween the control grid and the cathode of tube. 28 and the cathode isgrounded. The negative grid bias 36 which is applied to the grid of gastriode 25 is sufficient to block tubes 25. A plate supply 3S is fed tothe plate IIB of gas triode 26 through contacts 3 which are normallyclosed and a suitable line resistor Il I. The output of tube 26 leads tothe control grid 42 of its corresponding gas triode 2l. The cathode ofgas triode 2'. is grounded and the output circuit fed through itscorresponding character operating magnet 29. The plate supply for gastriode 2l is fed through normally open contacts I.

Baud cam I- has arranged around its edge 23 points which open contacts 2at the middle of each baud interval except one. These contacts areconnected serially with a source of operating power 43, contacts 6, thewinding 44 of ratchet relay 34, and ground. It will be-seen thatcontacts E are arranged to be operated by the signal through relay 65.The ratchet relay is equipped with some suitable device such as apneumatic chamber l5 which allows it to respond vquickly but causes itto return slowly. Actuated by the ratchet relay 3ft is contact l, thetongue of which is so arranged that it stays in the position in which itis left. Thus after it is opened by the ratchet relay 311, it will stayopen until it is closed by the point it on the clutch closing cam I5.The printer tapeV advance cam I t is arranged to close contacts I in theplate circuit of gas triode 2T Iso that the character operating magnet29 may be energized during a particular portion of the shaft rotation.It also closes contacts I which energizes the tape advance magnetv Silat the proper time.

The selection restoring cam I8 opens contacts 3 in the plate circuit ofgas triode 2t for a moment, once for each revolution of the shaft I3.Correction cam I'I operates contacts 5. These contactsvcooperate withcontacts 8 of relay 41 actuated in turn by the signal currents. The

f correction motor 35 drives gears 48 to advance or retard the roller lon cam I5 to determine the time when the clutch is to be engaged. Limitswitches 49 and 5G are-provided to prevent over correction beyond theuseful range of the correction device.

In Figure 3 curves a through lc are drawn to represent one revolution ofshaft I3. Curves a and b illustrate the photocell scanner output and theposition of contacts 6 for iigure 0 and letter E, respectively. Theyalso indicate by the dotted lines between the rs the intervals duringwhich the tape is stationary. It will be noted that in each case thetape stops at the end of the second spacing baud interval whichterminates a character and starts again one baud interval before thebeginning of the next character. Curve .c represents the action ofcontacts 2. Curves d and c represent the ratchet relay currents forcharacters 0 and E, respectively. It willbe noted that two successivepulses of this current occur immediately following the last markingsignal of the characters. As will appear, this causes the clutch to becontrolled and to take the positions shown in curves j and g for thecharacters 0 and E, respectively. Curve h illustrates the clutch`position versus time for a space interval. It will be noted that therecorder tape is advanced two baud intervals for a space interval, thusallow-l ing for the-space between words. Curves i and j illustrate theyintervals during which the character operating magnet current is on andthe tape advance magnet current is on, respectively. Curve lc representsthe position of contacts 5.

The operation of this invention may best be understood by reference toFigures l, 2 and 3. It will be assumed that one character has beenprinted and shaft I3 is in a position about one baud interval earlierthan the position shown in Figure 2. Let us also assume that the nextcharacter is figure 0. Contacts I have been closed for the actuation ofthe previous letter operating magnet. As cam Iadvances contacts 'I areclosed by its action and the clutch is engaged. This starts the tapeadvance and the photocell scanner 22 scans the tape Il) to produce thesignal currents shown in curve a, Figure 3. The bar 23 is moved to themarking position when the rst marking character starts. This allows thecode elements represented by the hollow squares on cam I9 to vpassContact linger 2d. At .the end of the third marking baud interval bar 23moves back to the spacing position and this allows the fourth baud codeelement represented by the solid square on the code segment I9 .to pass.As the shaft advances the code elements for iigure O are so placed thatthe contact nger 2d will not be touched and contacts 25 will not beopened. However, each and every other of the contact fingers 24. is, atsome point during the scanning of this character, interfered with by oneormore code elements. When contacts 25 are opened for any character,tubes 25 break down or fire thus biasing tubes 2'! so that they cannotbreak down.. Thus tubes 2l for all characters except4 ligure 0 arebiased beyond cut-off.v Contacts 25 for character 0 were not opened sothat tube 2G is blocked and tube Z'I is not biased and is readyto carrycurrent.

Atthe end of the twenty-second baud interval after the `code se-lectionhas taken place for all figures contacts I will be closed by the action0f cam I. and current will flow through the letter operating magnet 29for the gure 0 andl through the one unblocked tube il, thus causing thecharacter 0 to be printed.` After current has been established in tube2l selection restoring cam I8 momentarily opens contacts 3. This4interrupts the current intubesZI and sets them up ready for the nextcharacter. rI'he continued rotation of cam I5 opens contacts iinterrupting the current in tube 2l and setting it up for the nextcharacter.

The spacing between the marking elements of ligure 0 do not result inany action on contacts 1 since the ratchet relay is arranged so thatcontacts 'l will not open unless the ratchet is advanced twice insuccession at baud frequency. However, the second spacing baud followingthe last marking character causes the ratchet relay 45 to advance andopen-contacts '1, opening the clutch through the clutch control relay33. This stops the recorder tape I3 temporarily. When shaft I3 arrivesat the last baud position before that shown in Figure 2 cam E5 movesroller 51 which closes contact 'i and restarts the tape advance. When ithas advanced one space corresponding to a baud interval the firstmarking corresponding to the next character is scanned and the aboveaction repeated.

The action of the correction device may best be understood by referenceto Figure 2 and Figures 4a, 4b and 4c. This device is required tocompensate for inaccuracies in the lengths assigned to correspond to abaud interval on the Morse ink recorder tape. If these baud lengths areslightly less than that for which the tape puller wheel 2| is designedthen the tape advance will have to start later, while if the baud lengthis too great the tape advance will have to start earlier. Curves m, nand p illustrate the action of the correction device. rThese curvesrepresent an enlarged portion of curve lc of Figure 3. Curves m, n and pin Figure 4a correspond to the condition when the baud length on thetape is correct. It will be seen that when the tongue of contacts 5closes on the ground side relay 41 is closed on the spacing side Whichis also its ground Side. When the tongue on contacts 5 is moved to thepositive voltage side the signal moves the tongue of contacts 8 to themarking side which is also the positive voltage side. Thus no currentwill be passed to the correction motor 35. When the baud lengths are tooshort, as is shown by curves m, n and p in Figure 4b, the tongue ofcontacts 8 is on its marking side for an interval while the tongue ofcontacts 5 is on its ground Side. Thus a positive current will flowthrough the correction motor 35. When the bauds are too long, as isshown by curves m, n and p in Figure 4c, the tongue of contacts 8 is onthe spacing side for an interval while the tongue of contacts 5 is onthe positive voltage side. Thus a negative current flows through thecorrection motor. The motor is so arranged to turn in the directionrequired to delay the start of the tape advance when the baud lengthsare too short and to advance the start of the tape advance when they aretoo long. The correction motor drives gears u to advance or retard theroller 51 actuated by cam I5 and thus determines the time when theclutch is to be engaged.

It is possible to replace the code bar device 23 as described above witha semi-electronic device. Such modification is shown in Figure 5illustrating circuit components replacing code segments I9, bar 23,contact lingers 24, and contacts 25. Here instead of rendering grid 31of tube 26 positive by removing bias as in the arrangement of Fig. 2, apositive voltage is applied to grid 31 by means of a pair of vacuumtubes 5| and 52 associated with each code character. The screen grids 53and 54, respectively, of these two tubes have impressed upon them codesignals corresponding to the particular character for which they are towork, which local signals are generated by a plurality of code Wheelshaving signals corresponding to the code elements of the character whichthey represent. This modication requires a mechanical code wheel to bemounted on drive shaft I3 for each of the code combinations desired justas was required for the code signals of Fig. 1. The typical code wheel59 shown in Fig 5 again represents the gure 0. A cam follower arm 64 isarranged to follow code wheel 59 the full lines indicating its positionwhen the local signal elements are marking and the broken linesindicating its position for spacing elements. Two switch tongues 65 and66 are mechanically linked to cam follower 59 and are electricallyconnected to grids 53 and 54 of tubes 5I and 52 respectively, thevoltage being impressed upon one of them being reversed from thatimpressed on the other. Similarly, the control grids 55 and 56 of thesetwo tubes would have the photocell scanner output impressed on them, onebeing reversed from the other by means of switch tongues 62 and 63. Whenthe photocell scanner signal output applied to the grids corresponds tothe code signals applied to the screen grids the voltage applied to thecontrol grids would be opposite to that applied to their screen gridsthroughout that character and no current would be passed in either tube.However, when this is `not the case one tube or the other would carrycurrent at some time during the character. This will result in tube 26breaking down and from there on the action would be the same asdescribed above.

What is claimed is:

1. In a telegraph system utilizing stored code signals, means forgenerating code signal characters, a plurality of output circuits, meansfor supplying power to said output circuits, blocking means for each orsaid output circuits responsive to current new, and means applying acode signal to be translated and said generated characters to all saidblocking means except one in equal strengths out of phase whereby onlyone of said output circuits is operative.

2. In a telegraph system, apparatus for translating intelligenceexpressed in a given code, including a plurality of cams havingcongurations corresponding to the natures of the individual codeelements of the individual characters of said code, means to synchronizethe operation of said cams with the characters of said intelligence tobe translated, cam followers associated with each of said cams toproduce a voltage varying in accordance with the individual elements ofthe characters of said given code, a plurality of output circuitscorresponding to the individual characters of said code, output blockingcircuits associated with each of said output circuits, means to applyoperating potential to said blocking and said output circuits, meansresponsive to the individual elements of the characters of saidintelligence to energize said blocking circuits when the nature of theindividual code elements of said code cams differs from the nature ofthe corresponding code element of said intelligence character to blockthe associated output circuit, whereby only one of said output circuitsremains operative.

3. In a telegraph system, apparatus for translating intelligenceexpressed in a given code, including a plurality of cams havingconfigurations corresponding to the natures of the individual codeelements of the individual characters of said code, means to synchronizethe operation of area-93e saidcams with ith'e characters -of saidintelligence to be translated, cam followers associated with each ofsaid foams, means associated with said cam `followers to producevoltages varying in accordance with the individual code elements of thevcharacters of said code, -a plurality of -output circuits correspondingto the individual characterso said code, blocking means associated witheach of said output circuits, a control device coupled to reach of saidblocking means, said device being responsive to the individual elementsof the-'characters of said-code under consideration toenergize said`blocking means when rthe nature ofthe individual lcode elements of saidcode cams differs from the `naturelof the corresponding code element ofsaid intelligence character to block the associated youtput circuit,whereby only one of saidou'tput circuits remains operative.

4. In a telegraph system, apparatus for translating intelligenceexpressed in a given code, including a plurality of cams having'configurations corresponding to the natures of the individualcodeelements of the individualcharacters of said code, cam followersassociated with each of said cams, synchronous means to shift said camfollowers in accordance with the nature of the individual `code elementsof `the intelligence to be translated, a plurality of output Vcircuitscorresponding -to the individual characters of said code, Voutputblocking circuits associated with each of said output circuits, means toapply operatingpotentialto said blocking and said output circuits,energizing means associated with said cam .followers arranged toYenergize said blocking circuits when the nature of the individual codeelements of said code cams differs from the nature of the correspondingcode element of said intelligence character to block the associatedoutput circuit, whereby'only one of said output circuits remainsoperative.

5. In a telegraph system, apparatus for translating intelligenceexpressed in a given code, including a plurality of pairs of cams havingcomplementary configurations corresponding to the natures of theindividual code elements of the individual characters of said code, camfollowers associated with each of said Vpairs of cams, meanssynchronously to shift said cam followers with respect to the cams ofeach of said pairs in accordance with the individual code elements ofthe intelligence to be translated, a plurality of output circuitscorresponding to the individual characters of said code, output blockingcircuits associated with each of said output circuits, means to applyoperating potential to said blocking and said output circuits,energizing means associatedk with said cam followers arranged toenergize said blocking circuits when the nature ofthe individual codeelements of said pairs of code cams differs from the natureof thecorrespending code element of said intelligence character to block theAassociated output circuit, whereby only one of said output circuitsremains operative.

6. In a telegraph system, apparatus for translating intelligenceexpressed in a given code, including means to establish lcode potentialscorresponding to the individual elements of the characters of said code,said potentials varying 'in sign in accordance with 4the nature of theindi- Vidualelements of said characters, means responsive to theelements of the characters of said intelligence to establish signalvoltages varying in sign in accordance with the nature of the individualelements of said intelligence, means to d synchronize the establishmentof said vpotential and said voltages, a plurality of output circuitscorresponding to the individual characters of said code, blocking meansfor each of said outputcircuits, means to apply said code potentials andsaid signal voltages to said blocking means to block theassociatedfoutput circuits when the nature of the individual elements ofsaid code characters diiers from the nature of the correspondingelements of the intelligence character under consideration whereby onlyone of said output circuits is operative.

7. In a telegraph system, apparatus for translating intelligenceexpressed in a given code, including means to establish code potentialscorresponding to the individual elements of the characters of said code,said potentials varying in sign in accordance with the nature of theindividual elements of said characters, means responsive to the codeelements of said intelligence to establish signal voltages `varying insign in accordance with the nature of the individual code elements ofsaid intelligence, said voltages and said potentials being establishedin synchronisni, a plurality of output circuitsfcorresponding totheindividual vcharacters-of said code, blocking means foreach'of saidoutput circuits responsive to current flow, means to apply said codepotentials and said signal lvoltages Ito said blocking means to produce`current flow and block the associated output circuits when the 4natureof the individual elements of said code characters vdiffer from thenature ci the corresponding elements of said intelligence characterunder consideration whereby only the one of said output circuitscorresponding to the character under consideration is-operative.

8. In a telegraph system, apparatus for translating intelligenceexpressed in a given code. including means to establish code potentialscorresponding to the individual 'elements of the characters of saidcode, said potentials varying in sign in accordance with the 'nature ofthe individual elements `of said characters, and being synchronized withthe elements of the characters of `said intelligence underconsideration, means responsive to the elements of the characters ofsaid .intelligence to 'establish signal voltages varying in sign inaccordance with the nature of the individual elements of saidintelligence, a plurality of output circuits corresponding totheindividual .characters of said code, an output 'blocking circuit for.each of said output circuits responsive to current flow, a controlcircuit associated with each of said blocking circuits, means to applysaid ,code potentials and said signal voltages to said control circuitsto energize said output blocking circuits whenithe nature of theindividual elements of said code characters differ from the nature ofthe .corresponding elements of said intelligence character underconsideration whereby only 'the one of said output circuitscorresponding to .the character under consideration is operative.

9. In a Iprinting telegraph system, a printer for translating.intelligence expressed in a given code, including a `tape carryingvprinted characters of said code, means for scanning said printedcharacters to produce voltages corresponding to the individual elementsof said characters, said voltages varying in sign in accor-dance withthe nature of the individual elements of said charactersgmeans'toestablish potentials'con responding to each of thelcharacters of saidgiven code, said potentials varying in sign in accorde ance with thenature of the individual elements of said characters, a plurality ofoutput circuits corresponding to the individual characters of said code,blocking means for each of said output circuits, means to apply saidpotentials and said voltages to said blocking means to block the associated output circuits when the nature of the individual elements ofsaid code characters differs from the nature of the correspondingelements of the printed character under consideration whereby only theone of said output circuits corresponding to the character underconsideration is operative.

10. In a telegraph system, apparatus ior translating intelligenceexpressed in a given code, including an output circuit for eachcharacter of said code, blocking means for each of said output circuitsresponsive to current flow, means to produce voltages of polarity inaccordance with the nature of the individual elements of the characterof said intelligence under consideration, means to apply said voltagesto each of said blocking means, a code cam having a configurationcorresponding'to the individual elements of the code character which itrepresents for each of the characters of said code, means associatedwith each of said code cams to establish potentials of given sign to theassociated blocking means when the elements of each character are of onenature and to reverse the-sign of said potentials when the elements areof opposite nature, the operation of said code cams being synchronisedwith the character of said intelligence under consideration, saidvoltages and said potentials being applied to said blocking means insign relationship to alter current flow only by application ofpotentials and voltages having polarities representing characterelements of different nature to block the respective output circuitwhereby only the one of said output circuits corresponding to thecharacter of said code under consideration is operative.

11. In a telegraph system, apparatus for translating intelligenceexpressed in a given code, including an output circuit for eachcharacter of said code, blocking means for each of said output circuitsresponsive to current flow, a control circuit for each of said blockingmeans, means to produce signal voltages in accordance with the nature ofthe individual elements of the character of said intelligence Iundercon'- sideration, means to apply said signal voltages to each of saidcontrol circuits, a code cam having a configuration corresponding to theindividual elements oi the code character which it represents for eachof the characters of said code, means associated with each of said codecarns to establish potentials of given sign to the associated controlcircuits when the elements of each character are of one nature and toreverse the sign of said potentials when the elements are oi opipositenature, said potentials being produced in synchronism with saidvoltages, said voltages and said potentials being applied to saidcontrol circuit in sign relationship to alter current flow only byapplication ol voltages and potentials representing character elementsof different na ture to block the respective output circuit wheren byonly the one of said output circuits corresponding to the character ofsaid code under conu sideration is operative.

l2. In a telegraph system, a printer for translating intelligenceexpressed in a given code, including an output circuit having a gridcontrolled gaseous discharge device coupled. t@ lill@ Jurrespondingactuating magnet of said printer for each character of said code, anoutput blocking circuit having a further grid controlled gaseousdischarge tube coupled to the control grid of the associated outputcircuit, a control circuit for each of said blocking circuits, saidcontrol circuits each comprising a pair of electron discharge devices,connected in parallel, each having two control grids in seriesrelationship between cathode and anode electrodes, switch meansresponsive to the character of said intelligence under consideration toproduce voltages of one sign when the individual elements of said codecharacter are of one nature and to produce voltages of reverse sign whenthe elements are of opposite nature, a code cam having a configurationcorresponding to the individual elements of the code character which itrepresents for each of the characters of said code, switching meansassociated with said code cam to establish potentials of one sign whenthe individual elements of the code characters are of one nature and toestablish potentials of reverse sign when the elements are of oppositenature, means to apply said voltages to corresponding control grids ofsaid electron discharge devices, and means to apply said potentials tothe other control grids of said electron discharge devices to preventcurrent flow in each of said control circuits when the individualelements of each character under consideration are of the same nature asthat of the elements of the character to which the control circuitscorrespond whereby the associated output blocking circuit is inactiveand the associated output circuit remains operative to actuate thecorresponding printer magnet.

13. In a telegraph system, a printer for translating intelligenceexpressed in a given code, including an output circuit having a gridcontrolled gaseous discharge device coupled to the correspondingactuating magnet of said printer for each character of said code, anoutput blocking circuit having a further grid controlled gaseousdischarge tube coupled to the control grid of the associated outputcircuit, a control circuit for each of said blocking circuits, saidcontrol circuits each comprising a pair of electron control devicesconnected in parallel and each having two control elements in seriesrelationship, switch means responsive to the character of saidintelligence under consideration to produce voltages of given polaritywhen the individual elements of said code character are oi one natureand to reverse the polarity of said voltages when the elements are ofopposite nature, a code cam having a, configuration corresponding to theindividual elements of the code character which it represents for eachof the characters of said code, switching means associated with saidcode cam to establish potentials of one polarity when the individualelements of the code characters are of one nature and of rev rsepolarity when the elements are of opposite nature, means to apply saidvoltages to corresponding control elements of said devices, and means toapply said potentials to the other control elements of said devices toprevent current flow in each of said control circuits when theindividual elements of each character under consideration are of thesame nature as that of the elements of the character to which thecontrol devices correspond whereby the associated output blockingcircuit is inactive and the associated output circuit is operative toactuate the corresponding printer magnet.

le. In a telegraph system, apparatus for transvaeeres latingintelligence expressed in a given code,y including a plurality of camshaving configurations corresponding to the natures of the individualcode elements of the individual characters oi said code` means tosynchronize the operation of said cams with the characters of saidintelligence to be translated,` cam followers associated with each ofsaid cams, electric contacts cooperatively associated with said camfollowers, a plurality of outputvcircuits corresponding to theindividual characters of said code, output blocking circuits associatedwith each of said output circuits, means to apply operating potential tosaid blocking and said outputcircuits, circuitry interconnecting saidelectric contacts and said operating potential means and said blockingcircuits to energize said blocking circuits when the nature of theindividual code elements of said code cams diiers from the nature of thecorresponding .code element of said intelligence character to block theassociated output circuit, whereby only one of said output circuitsremains operative.

15. In a telegraph system, apparatus for translating intelligenceexpressed ina given code, includinga plurality of camshavingconfigurations corresponding to the natures of .the .individual codeelements of the indivdualcharacters of said code, means to synchronizethe operation of said cams with the characters of said intelligence tobeftranslated, cam followers associated with each ofsaid cams, electriccontacts associated with 12 saidvcam followers, aplurality'of outputcircuits .corresponding to the individual characters of said code,blocking means associated rwith each of said output circuits, control:circuitry intercoupling each of said blocking. means and each of saidelectric contacts and arranged to energize said blocking means whentlienature of -the inv dividual code-.elements of said vcoclecams dii-ersfrom the nature of the correspondingcode elements of said intelligence.character to block rthe associated output circuit, whereby only one ofsaid output circuitsremains operative.

JAMESLESLIE FINCH.

` REFERENCES CITED The following references :are of recordin the ile of`this patent:

UNTED STATES PATENTS Number lName Date 1,193,807 Lyons ,Aug. 8, 19161,205,460 Lyons. Nov.r 21, 1916 1,719,535 Davis July 2, v1929 2,111,154vNichols Mar. 15, 1938 2,131,202 AVan Mierlo et al. 1 Sept.. 27, 19382,354,733 Baldwin Aug. 1, 1944 OTHER REFERENCES American StandardDenitions of Electrical Terms, The American Institute of ElectricalEngineers, 1942; .65.65.600, p. 229.

